[dpdk-dev] random pkt generator PMD

Dumitrescu, Cristian cristian.dumitrescu at intel.com
Wed Jun 15 14:11:03 CEST 2016



> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Dumitrescu,
> Cristian
> Sent: Wednesday, June 15, 2016 12:26 PM
> To: Yerden Zhumabekov <e_zhumabekov at sts.kz>; dev at dpdk.org
> Subject: Re: [dpdk-dev] random pkt generator PMD
> 
> 
> 
> > -----Original Message-----
> > From: Yerden Zhumabekov [mailto:e_zhumabekov at sts.kz]
> > Sent: Wednesday, June 15, 2016 12:11 PM
> > To: Dumitrescu, Cristian <cristian.dumitrescu at intel.com>; dev at dpdk.org
> > Subject: Re: [dpdk-dev] random pkt generator PMD
> >
> >
> >
> > On 15.06.2016 16:43, Dumitrescu, Cristian wrote:
> > >
> > >> -----Original Message-----
> > >> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Yerden
> > >> Zhumabekov
> > >> Sent: Wednesday, June 15, 2016 10:44 AM
> > >> To: dev at dpdk.org
> > >> Subject: [dpdk-dev] random pkt generator PMD
> > >>
> > >> Hello everybody,
> > >>
> > >> DPDK already got a number of PMDs for various eth devices, it even has
> > >> PMD emulations for backends such as pcap, sw rings etc.
> > >>
> > >> I've been thinking about the idea of having PMD which would generate
> > >> mbufs on the fly in some randomized fashion. This would serve goals
> > >> like, for example:
> > >>
> > >> 1) running tests for applications with network processing capabilities
> > >> without additional software packet generators;
> > >> 2) making performance measurements with no hw inteference;
> > >> 3) ability to run without root privileges, --no-pci, --no-huge, for CI
> > >> build, so on.
> > >>
> > >> Maybe there's no such need, and these goals may be achieved by other
> > >> means and this idea is flawed? Any thoughts?
> > > How about a Perl/Python script to generate a PCAP file with random
> > packets and then feed the PCAP file to the PCAP PMD?
> > >
> > > Random can mean different requirements for different
> users/application, I
> > think it is difficult to fit this  under a simple generic API. Customizing the
> script
> > for different requirements if a far better option in my opinion.
> >
> > AFAIK, the thing about pcap pmd is that one needs to rewind pcap file
> > once pcap pmd reaches its end. It requires additional (non-generic)
> > handling in app code.
> 
> Yes, this is an obvious improvement that needs to happen to PCAP PMD.

Please note the PCAP file rewind code is already available as part of the source port in librte_port, it might be just straightforward to fit this code into the PCAP PMD.

Since the NICs generate packets forever, my recommendation is to have the loop/rewind mode as the default behavior for the reworked PCAP PMD, with potentially an option to disable the loop/rewind passed through dev args.



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